The general aim of this project is to examine metabolic processes in a respiratory epithelium. The specific current objective of these studies is to determine whether a short-term in vitro assay can be established which will have a high rate of correlation with the results of long-term carcinogenesis studies. It is hoped that such an assay might indicate situations affecting the susceptibility of the hamster respiratory tract to tumor induction and provide experiments with more rapid turnover than life-time studies.